1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to data processing systems in which it is wished to update out-of-date data stored by a plurality of destination computers with updated data stored by a source computer.
2. Description of the Prior Art
It is known to provide update mechanisms whereby updated data, such as updated versions of a computer program, updated database data, etc., may be automatically distributed from a central source to a plurality of destination computers via a computer network. Such mechanisms are, for example, known and used in the field of computer virus scanning for updating computer virus definition date to client computers quickly and efficiently when updated computer virus definition data becomes available. It is important that such updated computer virus definition data is made available at the destination computers rapidly in order to provide protection against computer virus threats. However, a problem arises in that many hundreds or thousands of destination computers may require the updated data and the amount of network traffic this can generate can overwhelm the computer network concerned and cause it to malfunction or excessively slow down.
It is known to provide mechanisms whereby a single source computer may send data to one or more destination computers via unicasting (point to point communication between two computers), multicasting (one computer communicating to a selected number of other computers) and broadcasting (one computer communicating with every other computer connected to its network). Such techniques are supported by network protocols such as TCP/IP and associated communications hardware (such as network switches) and provide one mechanism that can be used to control the amount of network traffic generated when delivering data from one source to many destinations.
Copending U.S. patent application Ser. Nos. 09/633,358, 09/944,114 and 09/678,692 describe various techniques for controlling the process of updating data held by a source computer to a plurality of destination computers.
Measures which can improve the efficiency and effectiveness of updating data via a computer network are strongly advantageous.